Aerospace Science and Technology
Mohammad Reza Salimi; Mohammad Taeibi Rahni; Abolfazl Amiri Hezaveh; Mehdi Zakyani Rodsari
Abstract
In present research, the interaction between single liquid droplet with particles inside a porous media is investigated numerically in two dimensions. The He’s model is used to simulate two phase flow and multiple relaxation time collision operator is implemented to increase numerical stability. ...
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In present research, the interaction between single liquid droplet with particles inside a porous media is investigated numerically in two dimensions. The He’s model is used to simulate two phase flow and multiple relaxation time collision operator is implemented to increase numerical stability. Simulations have performed in three non-dimensional body forces of 0.000108, 0.000144, 0.000180, porosity values of 0.75, 0.8, 0.85 and Ohnesorge range of 0.19-0.76. In the range of investigated non-dimensional parameters, two distinct physics of droplet trapping and break up have observed. The related results revels that for every values of investigated non-dimensional body forces and porosity, there is a critical Ohnesorge number that droplet breaks up occurs for larger values. This critical value decreases as non-dimensional body force and porosity increases. Based on these results, a droplet trapping or break up behavioral diagram is drown with respect to the investigated density ratio, Ohnsorge, Reynolds and Capilary numbers.
M.R. Salimi; M. Taeibi Rahni; Mahdi Ramezanizadeh
Volume 9, Issue 1 , March 2012
Abstract
A new design concept is introduced to control the near-wall integration between the hot-gas boundary layer and the cooling jets in order to enhance the adiabatic film cooling effectiveness of the gas turbine blades. In this new approach, another film cooling port, having a very low blowing ratio, which ...
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A new design concept is introduced to control the near-wall integration between the hot-gas boundary layer and the cooling jets in order to enhance the adiabatic film cooling effectiveness of the gas turbine blades. In this new approach, another film cooling port, having a very low blowing ratio, which prevents formation of the counter-rotating vortex pare, is applied just upstream of the main film cooling jet. The fluid injected from the small upstream port changes the flow pattern, resultsinwider horseshoe vortices in the span-wise direction, and generates a more uniform distribution of the coolant film. Also, this coolant fluid flows towards the low pressure region located just behind the main film-cooling hole. Therefore, by producing a cold layer of gas beneath the coolant jet and diverting the hot cross-flow gases into this area, it significantly improves the film cooling effectiveness, especially in the near field of the main jet. The obtained results show lower stream-wise velocity gradients near the wall, which considerably decreases the wall shear stresses, comparing to the regular film cooling holes.
